Results: Using self-assembling nanomaterials, MIT researchers have restored the sight of brain-damaged rodents. After cutting through a structure in hamsters’ brains necessary for vision, neuroscientist Rutledge Ellis-Behnke and colleagues injected the animals with a solution containing short chains of amino acids, called peptides, that when in contact with brain fluids assemble into nanoscale fibers. The resulting mesh of fibers bridges the gap left by the cut and prevents scar tissue from forming, thus allowing neurons to regrow and reëstablish preinjury signal pathways. Seventy-five percent of adult hamsters treated with the technique recovered enough vision to detect and turn toward food.

Why It Matters: Spinal-cord and brain injuries from accidents, strokes, and disease affect millions of Ameri-cans; many of these people never regain lost abilities and functions, largely because scar tissue and inhibitory chemicals prevent damaged tissue from healing. At least over short distances, the experimental nanomaterial seems to overcome these problems in neural tissue. The nanomaterial allows nerve cells to grow and reëstablish connections, which could restore human patients’ lost abilities to walk or talk, even as it restored sight in these experiments.

Methods: In separate experiments on young and adult hamsters, the researchers cut through a brain structure called the optic track, which conveys visual signals, thus blinding the hamsters in one eye. Soon after the cut was made, control animals received an injection of saline at the site of the injury, and test animals received an injection of the peptides. The researchers then tested the animals for the -ability to see and turn toward sunflower seeds and, after euthanizing them, examined their brain tissue to measure the regrowth of neurons.

Next Step: If large-animal studies go well, the treatment could be tested in humans starting within three years. Meanwhile, the researchers are developing ways to speed nerve regrowth, with the goal of reconnecting distant areas of the brain and spinal cord sepa-rated by larger injuries.